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We report a family with a clinical diagnosis of oculopharyngeal muscular dystrophy in which muscle biopsy showed mitochondrial changes such as cytochrome-c-oxidase-negative fibers and aggregates of mitochondria containing paracrystalline inclusions. Molecular analysis demonstrated a GCG expansion in the poly(A)-binding protein 2 (PABP2) gene and failed to demonstrate multiple deletions of mtDNA. We hypothesize that mitochondrial abnormalities may be a secondary phenomenon. This observation may suggest that the PABP2 gene could interfere in the posttranscriptional regulation of genes involved in mitochondrial function., (Copyright 2004 S. Karger AG, Basel)

Although many studies have been performed on nervous tissue pathology in Guillain-Barré syndrome (GBS), much less is known about pathological changes in skeletal muscle in this disorder. We have studied muscle biopsies from 5 patients with GBS, 5 patients with amyotrophic lateral sclerosis (control A), and 5 patients with polyarteritis nodosa (control B). We also examined muscle obtained after death from 7 patients without neurologic or muscular diseases (control C). By light microscopy, all specimens from patients with GBS exhibited necrosis and/or phagocytosis, none of which was observed in the other three controls. Neither small angulated fibers nor small group atrophy was found in patients with GBS and in control C, by contrast with controls A and B. Ultrastructurally, filamentous bodies, subsarcolemmal aggregates of mitochondria, accumulation of glycogen particles, and concentric laminated bodies were present much more frequently in patients with GBS than in all controls. Only GBS patients showed cytoplasmic bodies. These observation suggests that there is muscle involvement in the early stage of GBS and that these muscle changes may have an intimate and important relationship to the pathogenesis of GBS.

Satellite cells (SC) are present in all types of skeletal muscles. They can exhibit DNA replication and mitotic divisions throughout their life. Depending on the kind of muscle, a different number of SC is present. The aim of this study was to establish whether the differences in muscle metabolism are reflected in the quantitative ultrastructural evaluation of their SC. Two skeletal muscles of rats, soleus (SOL) with predominant slow fibers and extensor digitorum longus (EDL) with predominant fast ones, were studied. Morphometric analysis was performed according to the modified method of Weibel [Stereological Methods, vol 1: Practical Methods for Biological Morphometry. London, Academic Press, 1979]. In the SC of EDL mitochondria, rough endoplasmic reticulum and Golgi apparatus were less frequent as compared with the SOL. The volume fractions of these organelles were much higher in SC of SOL than in EDL. The ribosomes and polyribosomes were more densely packed in SC of SOL than in EDL. Ultrastructural morphometric evaluation demonstrated significant differences between the SC components of two different muscles: a slow (SOL) and a fast (EDL) one.

The ultrastructure of the extraocular muscles of patients affected by congenital nystagmus is still to be defined. Specimens obtained from patients suffering from either oculomotor congenital nystagmus or nystagmus associated with strabismus were studied and compared with specimens obtained from patients enucleated for various pathologies but not affected by any oculomotor system disorder. The scleral myotendinous junction and the muscle body (venter) were examined. In both these areas, damaged muscle fibers were found. 'Mitochondrial cores' and concentric myofibrils characterized the extraocular muscles of the patients with oculomotor congenital nystagmus. In the extraocular muscles of the patients affected by nystagmus associated with strabismus we also found mitochondria with concentric cristae surrounding a highly electron-dense spherical body and numerous, large rods. In conclusion, these data indicate that both contractile and mitochondrial modifications might be signs of an altered muscle function and seem to indicate that oculomotor congenital nystagmus should be included among the list of oculomotor myopathies.

Patients with chronic fatigue syndrome (CFS) suffer from disabling physical and mental fatigue. Abnormalities in mitochondrial function can lead to fatigue and weakness. Ultrastructural mitochondrial abnormalities have been reported to be present in CFS patients. We obtained percutaneous needle muscle biopsies from 15 CFS patients and 15 age- and sex-matched controls. We investigated previously reported ultrastructural abnormalites in CFS: subsarcolemmal mitochondrial aggregates, intermyofibrillar mitochondrial aggregates, mitochondrial circumference, area, pleomorphism and the presence of compartmentalization of the inner mitochondrial membrane. All of the steps of tissue processing, electron microscopy and data abstracting and analysis were performed in a totally blinded fashion. All of our data were rigorously quantified. We found no difference in any of these studied parameters between CFS patients and controls. Although there is no ultrastructural mitochondrial abnormality in CFS patients, other lines of evidence suggest the presence of a possible functional mitochondrial abnormality.

We studied a 67-year-old female who suffered from polymyositis associated with primary biliary cirrhosis (PBC). Liver dysfunction was revealed by a screening test. Antimitochondrial antibodies (AMA) and antinuclear antibodies were positive. Liver biopsy was compatible with PBC (Scheuer stage I). Four years later she showed severe weakness and atrophy on her four extremities. Laboratory examination showed a creatinine kinase level of 312 IU/l, IgM 416 mg/dl, and AMA titer 1:320. Muscle biopsy findings were compatible with polymyositis. Electron microscopic examination disclosed diffuse increase of mitochondria in subsarcolemma and intermyofibrils, which has not been reported until now in polymyositis associated with PBC.

Mitochondrial abnormalities have been previously reported in some patients with myotonic dystrophy (DM). The aim of the present paper was to study muscle mitochondria in 32 DM patients by morphological, biochemical (when suggested by morphology) and genetic analysis. A single ragged red fiber, but no cytochrome c oxidase-negative fibers were found in the muscle specimen of 1 patient. However, mitochondrial enzyme activities resulted within the normal range. An electron microscopy study showed no significant mitochondrial changes. Southern blot analysis did not reveal any mitochondrial DNA heteroplasmy in all 32 patients. An explanation for the discordant results between this study and some previous reports of mitochondrial alterations in DM might be that their occasional presence is not related to the disease but to ageing. Another possibility is that among patients with a myotonic dystrophy phenotype, a small subgroup of subjects with a mitochondrial disease may exist and be differentiated.

Four muscle biopsies from the quadriceps femoris muscle of children with symptoms suggesting mitochondrial encephalomyopathy were examined for morphological and biochemical differences. From a biochemical point of view, our patients showed a derangement of mitochondrial metabolism and in particular a marked deficit in the activity of cytochrome c oxidase. In all patients there was an abnormally high rise of lactate and pyruvic acid levels in blood before and after glucose loading. Results of morphological and enzyme histochemical studies showed smaller muscle fibre diameters than in normal children. Typical red ragged fibres and ultrastructural abnormalities in muscle mitochondria were present in 1 case only. Three patients showed focal changes in the distribution of some sarcoplasmic oxidative enzyme activities. The present findings suggest that the main metabolic disorder, pointed out by biochemical studies, is scarcely reflected by morphological and ultrastructural studies in the early stages of mitochondriopathies.

A 25-year-old woman had been complaining of episodes of muscle weakness, nausea and vomiting since the age of 10. Muscle biopsy showed free fatty acid accumulation and mitochondrial abnormalities. Mitochondrial DNA appeared to be normal at Southern analysis. Biochemical investigations demonstrated: glutaric aciduria type II, decreased levels of carnitine in liver and values at the lower level of normal in muscle, increased muscle carnitine palmitoyl transferase activity, partial cytochrome c oxidase and succinate cytochrome reductase deficiency in muscle homogenate. In isolated muscle mitochondria, cytochromes aa3, b and c were partially decreased, butyryl-CoA dehydrogenase and palmitoyl-CoA dehydrogenase activities were 10 and 54% of the normal, respectively. Muscle cell cultures did not show lipid storage. Low-lipid diet reduced critical episodes and lipid storage in muscle biopsy.

The purpose of this study was the evaluation of changes induced by training (swimming 1 h/day, 5 days/week, 6 weeks) and an anabolic hormone (nandrolone decanoate, intramuscular injections of 15 mg.kg-1 per week) on fiber size, capillarization and mitochondrial fraction of murine soleus muscle. The animals (n = 32) were divided into 4 groups: a control group (C), that received the arachis oil carrier; a steroid group (S), that received the hormone; a training group (T), and a group that was submitted to training and to the administration of hormone (S + T). The soleus muscle was selected for quantitative light- and electron-microscopic evaluation. The muscle fiber size was increased in group T and decreased in groups S and S + T. The axial length of capillaries per unit volume of muscle decreased significantly in groups S and T. The number of capillaries per number of fibers showed a significant decrease in groups S and S + T and an increase in group T. The mitochondrial content decreased in group S, which suggested that anabolic steroids can be harmful for these organelles. This hypothesis was confirmed by histological evaluation at the electron-microscopic level. Many swollen and disrupted mitochondria were found in groups S and S + T. The results suggest that administration of nandrolone decanoate may have some deleterious effects on the muscle respiratory system (capillaries and mitochondria).

Two sisters with chronic progressive external ophthalmoplegia (CPEO) and their in all 7 healthy children were investigated. Both ophthalmoplegic patients had histopathological changes typical of mitochondrial myopathy. The same type of muscular pathology was also found among the healthy children. The most common muscular changes were subsarcolemmal accumulation of pathological mitochondria, including vacuoles, abnormal cristae and sometimes also inclusion bodies. Biochemical studies showed partial complex III deficiency, with low succinate-cytochrome c reductase activity in 1 of the ophthalmoplegic patients. These findings suggest that CPEO is a slowly progressive muscle disease, starting early in life. The widespread occurrence among the children may indicate maternal inheritance.

A 20-year-old man with the characteristic findings of infantile onset Kearns syndrome is described. Morphological and biochemical investigations proved a mitochondrial disease which we believe to be the cause of the symptoms in various organs. We assume an autosomal-dominant inheritance, the marker sign of which is blepharoptosis in several family members. Characteristic clinical, morphological and biochemical findings, combined with an autosomal-dominant inheritance with very variable expression, mark the Kearns syndrome as an individual disease, not as a symptom complex (syndrome). Kearns disease can be divided into three forms--an infantile form ("Kearns-Sayre syndrome') with early onset, rapid progression, multisystemic involvement and a severe course; and a juvenile and an adult form with onset in the second, respectively third (or later) decades with a generally slower and more benign course and less widespread expression in various organ systems. Furthermore, the occurrence of a curious orthoptic abnormality is described, indicating one of the possible ways to avoid diplopia in chronic progressive external ophthalmoplegia: the coexistence of normal and gliding abnormal retinal correspondence.

Age-associated changes in the flight muscles of higher insects, using male housefly as an example, have been discussed. The duration of sustained flight activity declines with age. During the first trimester of adult life, the mitochondrial volume in the flight muscles increases by additional biosynthesis. Individual mitochondria become further enlarged by the fusion of adjacent organelles. In old flies, a small proportion of mitochondria show degenerative changes. In senile flies, focal areas of the flight muscles undergo cytolytic changes. A variety of metabolic changes involving enzyme activities, protein synthesis, substrate levels and bioenergetics have been reported in flight muscles of aging insects. The mechanism of the loss in flight capacity of old insects, however, remains unknown.

Six extraocular muscles of the river lamprey, Lampetra fluviatilis L., were studied with the light and electron microscope. On the basis of morphology and histochemistry three types of muscle fibres were distinguished: thin, thick mitochondria-rich and thick multifibrillar fibres. In the thin fibres, 2.8-22.4 microns in diameter, myofibrils are distributed peripherally and show strong ATPase activity. The mitochondria are located paraxially. In the thick mitochondria-rich fibres, 19.4-31.0 microns in diameter, myofibrils are also located peripherally, whereas the central part of the fibre is densely packed with very numerous mitochondria possessing tubular cristae. Thick multifibrillar fibres, with a diameter similar to that of the former type, contain thin myofibrils scattered over the entire cross-section of the fibre. The activity of myofibrillar ATPase is lower in both types of thick fibres than in the thin ones. The tubules of the T system were observed frequently only in the thick multifibrillar fibres. The extraocular muscles of the lamprey are composed of large quantities of muscle fibres. Thin and thick fibres do not form separate layers, but are more or less uniformly distributed throughout the muscle. Many muscle fibres show structural features suggesting their degeneration.

The case of a 66-year-old woman with progressive external ophthalmoplegia and involvement of the proximal muscles of the upper and lower limbs is described. EMG examinations show signs of myopathic involvement. Histochemical and biochemical studies exclude a primary defect in glycogenolysis. The authors stress the peculiarity of the histochemical findings, characterized by the rare associated appearance of both mitochondrial changes and glycogen accumulation in muscle fibres. The most prominent ultrastructural findings are evidence of increased glycogen, usually present in vesicles or in mitochondria, and changes in number, size and structure of mitochondria. Quantitative biochemical examination of muscle homogenates confirmed the increased content of glycogen in muscle fibres.

The effect of experimental tourniquet ischaemia on the fine structure of a rabbit's hind limb striated muscle was studied. The tourniquet time varied from 1 to 4 h. Samples were obtained from the tibialis anterior muscle 30 min after releasing the tourniquet, the contralateral limb serving as the control. As the first sign of ischaemia, dilatation of the sarcoplasmic reticulum was observed after a tourniquet blockade of 1 h. After 4 h ischaemia myofibrillar components showed advanced degeneration. Ultrastructural alterations were distinct in the mitochondrial morphology. After 2 h, the mitochondria showed moderate but clear condensation. After 3 h many mitochondria showed high amplitude swelling and structural disorganization. Total blockade of the limb circulation up to 4 h effects the energy-producing organelles in the first place, especially sarcoplasmic reticulum, T tubules and mitochondria prior to the alterations in myofilaments. Ischaemia extended up to 3 h induces sublethal damage to the muscle cells.

The present study has used histochemical and electron microscopic techniques to provide a quantitative comparison of the striated muscle fibre populations in the periurethral and perianal regions of the human levator ani muscle. Both regions consist predominantly of type I (slow twitch) fibres together with a small number of type II (fast twitch) fibres. However, marked differences have been demonstrated between the two regions with regard to proportions of the two fibre types, diameters of the constituent fibres and the distribution of muscle spindles. These observations are discussed in relation to the differing functional activity of the periurethral and perianal regions of the levator ani muscle.

The ultrastructure of the iris muscles and innervating nerves in patients with diabetes mellitus and approximately age-matched controls was examined by electron-microscopy. The specimens were obtained during cataract surgery. There were definite histopathological alterations at the nerve terminal innervating the dilator muscle, e.g. the presence of mitochondrial abnormalities, dense bodies and lamellar structures. No change was noted at the nerve terminal to the sphincter muscle. Moderate involvement of the muscle, especially at the sphincter, was observed in the specimens of diabetics. The control specimens had no change at the nerve terminals, while moderate change was observed at the sphincter muscle. Therefore, the change in the sphincter seen in the specimens of diabetics seemed to be mainly the result of the aging process, though the existence of early sympathetic neuropathy was confirmed.

Three types of fibre, dark (type 1), light (type 2) and intermediate, were distinguished in the caval sphincter muscle of the diaphragm in the harp seal (Pagophilus groenlandicus) using histochemical and electron-microscopic techniques. The dark fibre contained large peripheral aggregations of mitochondria, numerous lipid droplets and dense aggregates of glycogen granules. The same features were observed in the dark fibre of the diaphragm muscle too. In the light of the low oxidative enzyme activity and high lipase activity observed in the diaphragm and other skeletal muscles of the harp seal in previous studies, it is postulated that these mitochondrial aggregations and lipid droplets represent an adaptation for the generation of heat through non-shivering thermogenesis comparable to that in the brown adipose tissue. Such ability to generate and maintain heat by uncoupling the oxidative phosphorylation process should enable the caval sphincter muscle to function efficiently in regulating the cardiac return of blood from the inferior vena cava during a dive when the body temperature as a whole drops. The lack of the regional differences in the fibre composition of the harp seal diaphragm, as were reported in the rat diaphragm, is attributed to the seal's large body size, lower metabolic rate and diving habit.

3 adult women with distinct clinical pictures of progressive myopathy were studied. The morphological findings of biopsied skeletal muscle suggested the diagnosis of type II glycogenosis. Biochemical analysis confirmed a profound deficiency of alpha-1,4-glucosidase activity. Electrophoresis of muscle acid maltase showed the presence of one band in normal individuals. A very faint band with normal electrophoretic mobility was present in the patients' muscles. Muscle neutral maltase is composed of four bands in normal adult individuals: two of the four bands were clearly reduced in the muscles of the patients. The acid and neutral maltases were not significantly reduced in the patients' leukocytes. Acid maltase determination in urine made it possible to identify the homozygous, but not to completely segregate the heterozygous, from unaffected adult subjects.

Both organ culture (choriallantoic membrane) of striped muscle from mouse diaphragm and freeze-drying of myocardial cells presented very characteristic structures in mitochondria. The organ culture evidence 'rod-like structures' in the intracristal spaces of the cristae mitochondriales. It is believed that these structures are the central apparatus responsible for mitochondrial division. On the other hand, the freeze-dried mitochondria presented neither intracristal spaces nor a space in the outer mitochondrial membrane. Because these spaces appeared only after fixation and dehydration, it is discussed if they are really artifacts. The mitochondrial cristae appearing as united structures after the freeze-drying process have been compared to the rod-like structures appearing intracristally after organ culture and conventional preparation techniques.

A case of progressive external ophthalmoplegia is described, in which the onset of the illness was at 28--30 years, with fatigability and muscular pains in the lower limbs as presenting symptoms. At 36--37 years weakness of the mimic muscles also appeared and fatigability and muscular pains spread to the upper limbs: EMG examination showed signs of light myopathic involvement of the shoulder-girdle muscles, so that a muscular biopsy was performed (right deltoid). Histoenzymologic studies showed the presence of generally atrophic dark fibres, which can be brought about to red-ragged fibres. Ultrastructural study showed bizarrely shaped mitochondria, with dense matrix and circular and confluent cristae, which were found in fibres with plenty of indifferent sarcoplasm and with anomalies in myofibrils. No mitochondrial inclusions were seen.

The thoracic flight muscle from adult male NAIDM house flies was examined, from emergence to very old age. Thin sections stained with uranyl acetate and bismuth showed no myofibrillar or mitochondrial degeneration from 1 day to 19 days post-emergence, contrary to earlier reports. Some progressive loss in glycogen content and increase in mitochondrial size were observed for muscle from young to very old flies. However, there was no conclusive evidence of fusion of smaller mitochondria into larger ones with advancing age, despite exhaustive examination of representative sections of muscle samples of adult males of different ages.

The capacity for recovery of the normothermic left ventricular myocardium from a regional complete ischemia (RCI) was investigated using changes in the myocardial metabolic status (ATP, ADP, AMP, creatine phosphate (CrP), free creatine, glycogen, glucose, lactate) and alterations of the morphology as parameters. In dogs, an area of the anterior wall of the left ventricular myocardium was temporarily deprived completely of its blood supply by 5--7 overlapping ligatures extending into the heart cavity. The metabolites of the adenylic acid-CrP system returned to normal tissue levels after 30 and 60 min of RCI within 14 and 35 days of recovery, respectively; restoration averaged 82% after 100 min, 74% after 140 min, and 38% after 180 min of RCI after 5 weeks of recovery. At the same time glycogen amounted to 163% after 100 min, 114% min, and 65% after 180 min of RCI. The biochemical data correlated well with the structural changes in the affected myocardium, especially with the amount of de- and regenerating heart muscle cells. These obviously were functionally defect and were not comparable with normal structured and functioning heart muscle cells.

In the rabbit, baroreceptive intercalated and terminal receptor segments of the sinus nerve extend in the border region of adventitia and media of the carotid sinus wall. these receptors measuring 600-6,500 nm harbour a great number of mitochondria. They are either round, avoid or elongated. Round receptors are present over the whole area of the carotid sinus. Large receptors appear to be missing in the upper region, where only very elongated receptors are present, which are arranged in circular array in relation to the vascular axis. The baroreceptors are enveloped by special organelle-rich terminal cells of Schwann cell origin. The receptors have a special orientation in regard to the muscle-elastic system and to collagen. Receptors contain osmiophilic and laminated bodies, signs of degeneration and vesicles of different sizes. Many tubuli as well as glycogen granules are apparent. Some of these axoplasmatic changes appear to be related to metabolic processes (turnover) occurring in young and old animals.